Page 510 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 485

VetBooks.ir adenomas metastasise, in which case they are termed 2.95
adenocarcinomas.
Teratomas are solid or cystic tumours arising from
germ cells, which are benign and non- secretory.
They contain abnormally placed embryonic struc-
tures (e.g. hair, skin, nerves and blood vessels, and
even teeth and bone).
The extremely rare dysgerminoma consists of
homogeneous primordial germ-like cells, and it
is often lobulated or polycystic. The tumour tis-
sue is non-secretory, but can metastasise rapidly to
the thoracic and abdominal cavities. Hypertrophic Fig. 2.95 An enormously enlarged ovary, due to a
osteopathy (see p. 220) has been associated with haematoma, being removed surgically via laparotomy.
dysgerminoma. (Photo courtesy Tracey Chenier)

Clinical presentation
Most of these tumours are non-secretory and there- Management
fore mares exhibit no hormonal/cyclic aberrations Treatment is by surgical removal of the affected
and the contralateral ovary is normal. If the tumour ovary via laparotomy, colpotomy or laparoscopy.
becomes very large, it can cause abdominal pain by Laparoscopy is the method of choice except when
traction on the ovarian ligament or even rupture the ovary is very large.
of the ligament, leading to intra-abdominal haem-
orrhage. Fertility is not usually affected unless the Prognosis
tumour becomes so large that it displaces or impinges The prognosis following surgery is good for most of
on the reproductive tract, altering its conformation. these tumours because they are usually hormonally
Abdominal metastasis may lead to recurring inactive and benign, except in the case of dysgermi-
abdominal pain, colic, weight loss and/or ascites. In nomas and adenocarcinomas, which can metastasise
the case of dysgerminoma, the mare may show signs rapidly. The prognosis for these is poor unless ovari-
of hypertrophic osteopathy (see p. 220). A unilateral, ectomy is performed prior to metastasis.
enlarged, often cystic and irregularly-shaped, abnor-
mal ovary is evident on rectal palpation. OVARIAN HAEMATOMA

Differential diagnosis Definition/overview
Ovarian haematoma; GCT, other ovarian neoplasia, Ovarian haematoma is a unilateral ovarian enlarge-
lymphoma/lymphosarcoma. ment due to haematoma formation.

Diagnosis Aetiology/pathophysiology
Diagnosis is based on clinical signs and the identifica- A true ovarian haematoma is an uncommon event
tion of a unilateral, enlarged, often cystic, abnormal where there is intrafollicular haemorrhage. More
ovary on rectal palpation and ultrasonography. The commonly the term relates to the haemorrhagic
ultrasonographic appearance varies according to the anovulatory follicle (HAF). HAFs are a major prob-
tissue components of the tumour (Fig. 2.95). Serum lem as they reduce the pregnancy rates in mares and
hormone levels will help differentiate the cause of result in them foaling later in the year. An HAF is
the enlarged ovary. In dysgerminoma, serum testos- generally a follicle that does not ovulate properly
terone levels may be very high (up to 2500 pg/ml), (an infertile process) but goes on to fill with blood.
with low progesterone levels. Diagnosis is confirmed A persistent anovulatory follicle (PAF) is a follicle
on laparoscopy/laparotomy and histopathology of that does not ovulate, does not bleed internally and
the ovary following removal. remains a feature on the ovary.